TABLE 1.
Characteristics of the study population from the China Health and Nutrition Survey by quintile (Q) of monosodium glutamate (MSG) intake and survey year1
| Characteristics | 1991 |
1993 |
1997 |
2000 |
2004 |
2006 |
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| Q1 | Q5 | P | Q1 | Q5 | P | Q1 | Q5 | P | Q1 | Q5 | P | Q1 | Q5 | P | Q1 | Q5 | P | |
| No. of participants | 518 | 518 | 470 | 470 | 523 | 521 | 677 | 677 | 882 | 882 | 886 | 886 | ||||||
| MSG intake (g/d) | ||||||||||||||||||
| Median | 0.4 | 4.2 | 0.4 | 4.6 | 0.5 | 5.4 | 0.6 | 5.9 | 0.5 | 4.7 | 0.5 | 4.7 | ||||||
| Interquartile range | 0.2–0.5 | 3.4–5.6 | 0.1–0.6 | 3.8–6.2 | 0.3–0.6 | 4.5–6.9 | 0.4–0.8 | 5.1–7.3 | 0.3–0.6 | 3.6–6.1 | 0.3–0.6 | 3.8–6.0 | ||||||
| BMI (kg/m2) | 21.5 ± 2.72 | 22.5 ± 3.1 | <0.01 | 21.7 ± 3.0 | 22.9 ± 3.2 | <0.01 | 22.1 ± 2.9 | 22.9 ± 3.2 | <0.01 | 22.5 ± 3.1 | 23.8 ± 3.5 | <0.01 | 23.0 ± 3.5 | 23.7 ± 3.6 | <0.01 | 23.1 ± 3.4 | 23.8 ± 3.6 | 0.83 |
| Age (y) | 38.5 ± 13.1 | 39.1 ± 12.1 | 0.52 | 40.1 ± 13.4 | 40.6 ± 11.7 | 0.80 | 41.3 ± 12.7 | 43.5 ± 13.1 | 0.01 | 43.7 ± 12.6 | 45.1 ± 12.5 | <0.01 | 45.7 ± 12.4 | 47.2 ± 11.8 | 0.11 | 45.7 ± 12.7 | 50.2 ± 12.3 | <0.01 |
| Female (%) | 53.1 | 51.9 | 0.15 | 55.5 | 51.2 | 0.75 | 55.1 | 50.7 | 0.26 | 55.2 | 47.6 | 0.04 | 55.7 | 49.6 | 0.11 | 56.7 | 50.3 | 0.08 |
| Current smoker (%) | 32.3 | 39.2 | <0.01 | 30.8 | 35.7 | 0.34 | 29.0 | 32.6 | 0.40 | 28.8 | 34.8 | 0.19 | 28.9 | 33.1 | 0.38 | 27.6 | 30.5 | 0.07 |
| Alcohol consumption (%) | 7.1 | 8.7 | 0.76 | 8.3 | 8.3 | 0.13 | 12.1 | 5.4 | <0.01 | 9.3 | 12.0 | 0.049 | 9.0 | 9.4 | 0.32 | 8.8 | 8.6 | 0.16 |
| Education (y) | 6.0 ± 4.2 | 6.9 ± 3.9 | <0.01 | 6.4 ± 3.9 | 7.4 ± 4.0 | <0.01 | 6.6 ± 3.9 | 6.9 ± 4.1 | 0.38 | 6.9 ± 4.0 | 8.0 ± 3.8 | <0.01 | 7.6 ± 3.9 | 8.1 ± 3.8 | 0.13 | 7.8 ± 4.3 | 7.5 ± 4.1 | 0.42 |
| Individual income (RMB)3 | ||||||||||||||||||
| Median | 2861 | 3190 | 0.04 | 3211 | 3845 | <0.01 | 3742 | 4485 | <0.01 | 4603 | 6561 | <0.01 | 5889 | 6943 | 0.12 | 7316 | 6855 | 0.20 |
| Interquartile range | 1605–4333 | 2078–4750 | 1876–5550 | 2517–6278 | 1939–6397 | 2365–7986 | 1950–8099 | 3365–10,254 | 2149–10,839 | 2722–11,778 | 2941–13,206 | 2451–12,944 | ||||||
| Physical activities (MET-h/wk)4 | ||||||||||||||||||
| Median | 362.3 | 259.9 | <0.01 | 330.8 | 233.2 | <0.01 | 313.4 | 224.6 | <0.01 | 315.5 | 182.5 | <0.01 | 194.0 | 150.9 | <0.01 | 208.2 | 166.1 | 0.02 |
| Interquartile range | 170.5–583.6 | 130.8–453.5 | 144.0–523.7 | 107.3–420.0 | 136.1–537.9 | 100.7–462.1 | 126.9–481.1 | 100.0–377.8 | 81.4–407.8 | 57.2–358.9 | 78.8–390.5 | 44.6–395.6 | ||||||
| Total energy intake (kcal) | ||||||||||||||||||
| Median | 2448 | 2563 | <0.01 | 2341 | 2423 | <0.01 | 2238 | 2434 | <0.01 | 2195 | 2425 | <0.01 | 2111 | 2219 | <0.01 | 2000 | 2262 | <0.01 |
| Interquartile range | 2129–2830 | 2210–3006 | 1993–2702 | 2061–2855 | 1834–2727 | 1986–2995 | 1780–2656 | 1985–2877 | 1722–2554 | 1734–2690 | 1578–2474 | 1791–2760 | ||||||
| Daily nutrient intake | ||||||||||||||||||
| Sodium (g/1000 kcal) | 2.3 ± 1.2 | 3.2 ± 1.5 | <0.01 | 2.3 ± 1.1 | 3.3 ± 1.5 | <0.01 | 1.9 ± 1.1 | 3.2 ± 1.7 | <0.01 | 2.2 ± 1.2 | 3.2 ± 1.8 | <0.01 | 2.0 ± 1.1 | 3.1 ± 1.5 | <0.01 | 2.0 ± 1.1 | 2.8 ± 1.4 | <0.01 |
| Potassium (mg/1000 kcal) | 682.7 ± 158.0 | 716.2 ± 194.8 | <0.01 | 690.0 ± 169.3 | 716.8 ± 180.9 | 0.32 | 683.0 ± 182.3 | 681.9 ± 200.2 | <0.01 | 707.8 ± 270.1 | 750.9 ± 252.6 | <0.01 | 729.6 ± 228.3 | 734.7 ± 236.8 | 0.08 | 806.2 ± 236.9 | 771.2 ± 237.0 | <0.01 |
| Phosphorus (mg/1000 kcal) | 429.6 ± 70.9 | 456.3 ± 82.6 | <0.01 | 438.1 ± 77.8 | 451.6 ± 82.6 | 0.02 | 417.0 ± 75.8 | 425.6 ± 93.8 | <0.01 | 426.8 ± 101.2 | 425.5 ± 110.2 | <0.01 | 451.3 ± 93.0 | 441.6 ± 85.8 | 0.31 | 464.7 ± 83.3 | 457.9 ± 88.9 | <0.01 |
| Carbohydrate (g/1000 kcal) | 159.3 ± 23.7 | 148.8 ± 26.5 | <0.01 | 157.6 ± 25.5 | 142.5 ± 28.2 | <0.01 | 152.7 ± 30.4 | 137.7 ± 33.5 | <0.01 | 147.9 ± 28.3 | 133.5 ± 30.8 | <0.01 | 149.9 ± 29.6 | 139.5 ± 32.0 | <0.01 | 147.6 ± 29.6 | 138.6 ± 30.4 | <0.01 |
| Total fat (g/1000 kcal) | 26.3 ± 10.0 | 30.9 ± 11.5 | <0.01 | 26.9 ± 10.8 | 33.4 ± 11.8 | <0.01 | 29.4 ± 12.3 | 36.5 ± 15.2 | <0.01 | 31.3 ± 11.5 | 37.0 ± 13.4 | <0.01 | 29.4 ± 11.7 | 34.5 ± 13.3 | <0.01 | 30.4 ± 12.2 | 34.7 ± 13.5 | <0.01 |
| Fiber (g/1000 kcal) | 4.5 ± 2.1 | 4.2 ± 1.9 | 0.22 | 4.4 ± 2.3 | 4.2 ± 1.7 | 0.19 | 4.7 ± 3.8 | 4.2 ± 2.6 | 0.16 | 4.9 ± 4.8 | 5.2 ± 10.8 | 0.47 | 5.1 ± 3.0 | 4.9 ± 3.0 | 0.10 | 5.4 ± 2.4 | 4.9 ± 2.5 | <0.01 |
| Total protein (g/1000 kcal) | 29.5 ± 5.3 | 29.9 ± 5.9 | 0.10 | 29.3 ± 5.9 | 30.6 ± 6.4 | <0.01 | 29.1 ± 5.9 | 28.9 ± 6.5 | 0.03 | 29.3 ± 6.7 | 30.8 ± 7.8 | <0.01 | 30.9 ± 6.8 | 29.6 ± 7.4 | <0.01 | 31.4 ± 6.4 | 30.9 ± 6.7 | 0.02 |
1
MET-h, metabolic equivalent hours; RMB, Chinese dollar. Differences across all quintiles were obtained by using ANOVA, the Kruskal-Wallis test, or the chi-square test.
2
Mean ± SD (all such values).
3
Individual income refers to total individual income inflated to 2006.
4
Physical activity included 4 aspects: occupational activity, home activity, leisure activity, and transportation activity. The former 2 aspects were measured in all surveys from 1991 to 2006, and the latter 2 aspects were measured since 1997.